The VFP test team is busting butt to test all of the new features for VFP 9 and to make sure that this version of VFP is the most stable ever. We were very happy with the overall robustness of VFP 8 - one customer who sells a shrink-wrapped app claims that service calls involving crashes dropped dramatically after recompliing and distributing the app on VFP 8.
For VFP 9, we're using new and even more advanced tools that check memory usage, test code coverage, and other stuff. We are benefiting from Microsoft's security initiative in that there are a lot of internal tools that look for questionable code practices. VFP is a mature application and there are blocks of code that are unmodified since the 80's. So sometimes we find and fix things that nobody ever considered before; this ramps up robustness.
Very soon now, we'll be releasing a public beta and you'll see what I'm talking about. I can't wait for DevCon where I can talk to you in person about VFP 9.